It is generally known that currently available motion control systems that are designed to move an object in more than one degree of freedom (DoF) include a separate motor or actuator for each DoF. More specifically, at least two motors or actuators are needed to implement 2-DoF motion, at least three motors or actuators are needed to implement 3-DoF motion, and so on. Consequently, mechanisms that involve more than one DoF tend to be somewhat large and cumbersome, and therefore inefficient.
While electronics and sensor technologies have gotten significantly smaller in recent years, mechanical motion technology has not kept up. This is why motion systems such as pan/tilt mechanisms are typically not used on smaller platforms, such as mini- or micro-UAVs (unmanned air vehicles) and micro-satellites. Robotics systems, which depend on multi-DoF motion control, must simply put up with the inherent inefficiencies of current motion-on-motion systems.
One solution to the above-described problems is disclosed in U.S. Pat. No. 7,675,208, entitled “Global Pointing Actuator.” The actuator disclosed therein includes a spherical stator with a “latitude coil” and a “longitude coil” wound thereon. This actuator, however, also exhibits certain drawbacks. For example, while it can move its associated armature, and thus a device coupled to the armature, in two degrees of freedom by applying direct current (DC) to one or both coils, it cannot do so in three degrees of freedom.
Hence, there is a need for a multi-degree of freedom electromechanical machine that is relatively smaller, less cumbersome, and more efficient than known devices and/or can move in three degrees of freedom. The present invention addresses at least these needs.